The primary purpose of this project is to describe and evaluate the distribution of cancer occurrence in the United States in terms of age, sex, race, place, and time in order to identify subgroups of the population that offer possibilities for mortality reduction through intervention. Cancer incidence, mortality, and survival rates are analyzed using biostatistical techniques. A marked increase in brain cancer incidence rates during the 15-year period 1973-1987 in SEER program areas was investigated using age-period-cohort models. Analyses for white males and white females aged 15-84 at diagnosis showed little effect of period (year of diagnosis) and a significant effect of cohort (year of birth). In collaboration with researchers in the Environmental Epidemiology Branch, HHV-6 antibodies in Hodgkin's disease patients were evaluated. Serum samples were taken from each of 37 patients with Hodgkin's disease at the time of diagnosis and at l-, 3-, and 5-years of follow-up. Repeated - measures methods showed a declining HHV-6 antibody pattern for patients who responded to therapy, whereas patients with more severe disease had increasing antibody titers. A retrospective cohort study, done in collaboration with investigators in the Clinical Epidemiology Branch, was designed to detect the effects of cancer and its treatment on childhood patients who survived to adulthood. The risk for early menopause among female members of this cohort was determined and compared to the risk among sisters of the survivors. Survival analysis methodology was used to estimate the proportion still menstruating as a function of age and to examine other factors affecting the hazard of menopause under the proportional hazards model. Survivors were found to be at an increased risk for early menopause. The risk was primarily a function of age and the type of treatment received for cancer. In another study based on this cohort, development of the cigarette smoking habit among 1,406 survivors who were nonsmokers when their cancer was diagnosed was compared to that among 2,236 sibling controls. Using conditional maximum likelihood methods, the smoking rate at last follow-up among survivors was found to be 79% of the rate among controls.